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A new fossil find suggests that some ancient sharks may have survived a mass extinction event 250 million years ago. Called the Great Dying, the event marked the end of the Permian and the beginning of the Triassic geologic periods and probably wiped out many fish groups.

But fossil teeth and other relics found in a region of southern France covered by a deep ocean roughly 135 million years ago suggest that some now-extinct sharks probably swam down into deep-sea hideouts to survive the extinction event. Fossils from these deep-sea refuges may harbor even more information about how ancient fishes evolved, scientists suggest October 29 in Nature Communications.